VOL. 11 May ISSUE YEAR 2010
in Vol. 11 - May Issue - Year 2010
Tools & Technology for a demand-Surface Technology
Dr.-Ing. Karsten R
Hydrostatic tool - type HG6
Whirl rolling head HGW13 for deep rolling of helical shafts
Tools of type RIOA allows the simultaneous counterboring, skiving and roller burnishing of cylinder tubes in one pass
MFN continues its interview series and approached ECOROLL AG, one of the world’s leading manufacturers of tools for roller burnishing, deep rolling and cylinder tube processing to talk about the technology and process itself. Dr.-Ing. Karsten Röttger is the CEO of ECOROLL AG Werkzeugtechnik since 2002. The company has grown strongly in recent years and is well prepared for the future.
(?) MFN: Dr. Röttger, for readers who don’t know ECOROLL, please describe your product range!
(!) K. R.: ECOROLL AG develops, manufactures and sells tools for the roller burnishing and deep rolling technologies, often conventionally referred to as "rolling", and furthermore combined tools for the cylinder tube manufacturing. The latter provide for a combined treatment of cylindrical tubes bores, typically used on deep-hole boring machines. These tools provide simultaneous skiving and roller burnishing of cylindrical tubes up to 15 meters or more in length and diameters up to 500 mm in one pass. The latest generation even provides a triple treatment - counter boring, skiving and roller burnishing. This brings the customer further significant increases in productivity.
For the tools in the field of roller burnishing and deep rolling, ECOROLL offers a wide range of different mechanical and hydrostatic versions offering customers an optimal solution for individual application requirements.
(?) MFN: What are the typical applications for your tools?
(!) K. R.: Our tools can be used for a wide range of different applications. Most important are applications in the automotive industry and mechanical engineering in general. Furthermore medical technology, shipbuilding and energy technology are domains where Ecoroll tools are in service day by day. Finally aerospace engineering is an important sector which had a promising development through the previous years.
(?) MFN: You spoke of the misuse of the word "rolling", what do you mean?
(!) K. R.: Some users and even competitors consider roller burnishing and deep rolling as being the same and call either one "rolling". Here ECOROLL presents a contrary opinion. Both technologies are clearly distinct from each other. It already starts with the main objective the customer wants to achieve. When a customer only wants to achieve a surface improvement in the form of a characteristic value for roughness such as Rz or Ra, this is roller burnishing. But if the customer seeks to extend the component life, this is deep rolling. The technologies are therefore clearly distinguished: on the one hand roller burnishing and on the other hand deep rolling. For each of these technologies you need adapted tools to achieve best results.
(?) MFN: Please explain the difference between roller burnishing and deep rolling in more detail.
(!) K. R.: As mentioned earlier, the objective of roller burnishing is to achieve a specified surface quality. In contrast, during deep rolling, the equalization of the surface is also a remarkable aspect. But however the main aspects of deep rolling are the strain hardening and the induction of compressive residual stresses into the rim zone of the component in order to increase the fatigue strength of dynamic loaded components.
Deep rolling is the only mechanical method to increase fatigue strength which combines the following characteristics:
• smoothing the surface,
• increasing the hardness or strain hardening and
• the induction of compressive residual stresses into the rim zone of components.
(?) MFN: Many of our readers are related to the general technology sector, "Surface treatment". What are the advantages of deep rolling compared to shot peening or other methods?
(!) K. R.: Deep rolling is not a panacea. If you look at the range of components considered to be processed, you realize quickly that because of accessibility, not every part geometry can be processed by deep rolling.
Deep rolling however, offers some advantages both in cost reduction as well as in technology. The cost of a deep rolling tool is many times less than, for example, the cost of a shot peening machine. In addition, customers can use our tools in the existing production lathes and milling centres saving money and space for additional expensive equipment. Moreover, the customer has the ability to deep roll the component in one setting directly following a cutting process. In the end, the customer has not only reduction of cost, but also an increase of production efficiency due to extremely low set-up times.
Other advantages of deep rolling compared to shot peening and other methods are the smoothing of the component surface and a greater magnitude and deeper penetration of compressive residual stresses. In summary, this means a greater increase in component life due to deep rolling than would otherwise be the case.
(?) MFN: What are the advantages of finish rolling with ECOROLL tools compared with procedures such as grinding, polishing, honing, etc., which are also used to achieve a specific surface?
(!) K. R.: Similar to deep rolling, ECOROLL tools can be used on existing lathes and milling centres. Lower investment costs are incurred and the customer gets an increase in productivity due to the part being machined and roller burnished in one set-up on the same machine. It is interesting that we have seen many customers switch from competitors tooling to using our products. Our experience of providing high quality tooling along with our strong customer service is very attractive to customers. They benefit from a highly trained sales team that can help give advice and arrange for tool demonstrations or trials.
(?) MFN: You also deal heavily in research and development for new tools and enhancements. What were ECOROLL’s significant improvements or innovations of the past 12 months?
(!) K. R.: Our company invests heavily in research and development. By continuing to improve processes and bring new products to market, we will continue to remain a leader in the industry. As examples of new developments, this past year ECOROLL developed the whirl rolling head and segmented cage for skive burnishing tooling. By using the whirl rolling head on whirling machines, it is possible to deep roll helical shafts after metal cutting. And the segmented cage for our combined tools from the area of the cylinder tube production allows the customer a fast and cost-effective replacement of wear parts of the roller burnishing head.
(?) MFN: What developments are you planning for the future?
(!) K. R.: Here at ECOROLL, we strive to achieve continuous development and improvement of our entire product range. This includes improving our process control for deep rolling applications and further developments and innovations in all our tools. Sometimes it is only small changes that allow the customer to optimize their process parameters and thus increase efficiency. But we attach great importance to offering our customers the best possible solution for now and into future.
MFN would like to thank Dr.-Ing. Karsten Röttger for this interview.